Managing CNAME records

Table of Contents

The instructions in this article assume you’re familiar with the CNAME record format and usage.

Add a CNAME record

To add a CNAME record

In the record editor, click Add and select CNAME to add a new CNAME record.

Enter the CNAME record information.

Name: the subdomain you want to create the record for, without the domain name. For example, if you want to represent www.example.com enter www. Leave it blank to represent the root domain example.com.

Content: the target host name this host will point to. It must be a host name (e.g. foo.bar.com) and not a URL (e.g. http://foo.bar.com or http://foo.bar.com/foo are invalid).

As with any other DNS record, you can configure:

TTL: the record time-to-live.

Once you’re ready, click Add Record to confirm and create the record.

The record is created and visible in the record list.

Update a CNAME record

To update a CNAME record

In the record editor, search the record and click on the pencil icon to edit it.

Update the information and click Update Record to save the record.

Remove a CNAME record

To remove a CNAME record

In the record editor, search the record and click on the trash icon to delete it.

Confirm the dialog to delete the record.

Common CNAME errors

Cannot add a new record where a CNAME exists

To understand the error, it’s important to understand that a CNAME points a whole subdomain to another name in the domain name system. If you have another record on that subdomain, you can’t add a CNAME, as that CNAME would render the other records useless. Let’s look at an example:

Let’s assume there’s an MX record on email.example.com, and you try to add a CNAME on that exact subdomain (email.example.com). If you added the CNAME, it would override the subdomain (email.example.com) and render the MX record useless, leading to a lot of potential confusion when email stops. To counter this potential confusion, the domain name system does not allow other records alongside a CNAME.

You can achive a similar behavior as a CNAME with a ALIAS record. If you want a sub-domain to always resolve to the IP address of another domain, you can use a ALIAS record pointing to that domain. You should only do this if you absolutely need it, as the ALIAS record has a small amount of additional overhead when compared to A and CNAME records.